/ Thesaurus / S Synonyms of spark plug Find synonyms for: Noun1. spark plug, sparking plug, plug, electrical deviceusage: electrical device that fits into the cylinder head of an internal-combustion engine and ignites the gas by means of an electric sparkWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: languid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language